Search Results

Search found 23809 results on 953 pages for 'message driven bean'.

Page 78/953 | < Previous Page | 74 75 76 77 78 79 80 81 82 83 84 85  | Next Page >

  • error using rename function in PHP.

    - by Catfish
    I keep getting this error, although the file still gets moved into the correct directory. Anybody know why i'm getting this error? Warning: rename(../Images/uploaded/1162504_56863010.jpg,../Images/uploaded/Portraits/1162504_56863010.jpg) [function.rename]: No error in D:\Data\Websites\wamp\www\StephsSite\PHP\addImage.php on line 21

    Read the article

  • Deleting a resource in a Cucumber (Capybara) step doesn't work

    - by Josiah Kiehl
    Here is my Scenario: Scenario: Delete a match Given pojo is logged in And there is a match with the following: | game_id | 1 | | name | Game del Pojo | | date_and_time | 2010-02-23 17:52:00 | | players | 2 | | teams | 2 | | comment | This is an awesome comment | | user_id | 1 | And I am on the show match 1 page And show me the page When I follow "Delete" And I follow "Yes, delete it" Then there should not be a match with the following: | game_id | 1 | | name | Game del Pojo | | date_and_time | 2010-02-23 17:52:00 | | players | 2 | | teams | 2 | | comment | This is an awesome comment | | user_id | 1 | If I walk through these steps manually, they work. When I click the confirmation: Yes, delete it, then the match is deleted. Cucumber, however, fails to delete the record and the last step fails. And I follow "Yes, delete it" # features/step_definitions/web_steps.rb:32 Then there should not be a match with the following: # features/step_definitions/match_steps.rb:8 | game_id | 1 | | name | Game del Pojo | | date_and_time | 2010-02-23 17:52:00 | | players | 2 | | teams | 2 | | comment | This is an awesome comment | | user_id | 1 | <nil> expected but was <#<Match id: 1, name: "Game del Pojo", date_and_time: "2010-02-23 17:52:00", teams: 2, created_at: "2010-03-02 23:06:33", updated_at: "2010-03-02 23:06:33", comment: "This is an awesome comment", players: 2, game_id: 1, user_id: 1>>. (Test::Unit::AssertionFailedError) /usr/lib/ruby/1.8/test/unit/assertions.rb:48:in `assert_block' /usr/lib/ruby/1.8/test/unit/assertions.rb:495:in `_wrap_assertion' /usr/lib/ruby/1.8/test/unit/assertions.rb:46:in `assert_block' /usr/lib/ruby/1.8/test/unit/assertions.rb:83:in `assert_equal' /usr/lib/ruby/1.8/test/unit/assertions.rb:172:in `assert_nil' ./features/step_definitions/match_steps.rb:22:in `/^there should (not)? be a match with the following:$/' features/matches.feature:124:in `Then there should not be a match with the following:' Any clue how to debug this? Thanks!

    Read the article

  • Value objects in DDD - Why immutable?

    - by Hobbes
    I don't get why value objects in DDD should be immutable, nor do I see how this is easily done. (I'm focusing on C# and Entity Framework, if that matters.) For example, let's consider the classic Address value object. If you needed to change "123 Main St" to "123 Main Street", why should I need to construct a whole new object instead of saying myCustomer.Address.AddressLine1 = "123 Main Street"? (Even if Entity Framework supported structs, this would still be a problem, wouldn't it?) I understand (I think) the idea that value objects don't have an identity and are part of a domain object, but can someone explain why immutability is a Good Thing? EDIT: My final question here really should be "Can someone explain why immutability is a Good Thing as applied to Value Objects?" Sorry for the confusion! EDIT: To clairfy, I am not asking about CLR value types (vs reference types). I'm asking about the higher level DDD concept of Value Objects. For example, here is a hack-ish way to implement immutable value types for Entity Framework: http://rogeralsing.com/2009/05/21/entity-framework-4-immutable-value-objects. Basically, he just makes all setters private. Why go through the trouble of doing this?

    Read the article

  • Error including image in Latex

    - by euphoria83
    I am getting the following error while compiling my Latex File : ! LaTeX Error: Cannot determine size of graphic in tree.jpg (no BoundingBox). Why do I get this error ? What has this to do with an .eps file ? Infact, I could compile it fine with MacTex on my machine. But when I submit it online to a scientific journal for publication, it compiles it on the server and sends me the resultant PDF which as all these error that prevent it from compiling. I am using the following syntax for including the images : \begin{figure}[!h] \begin{center} \scalebox{0.45}{ \includegraphics{tree.jpg}} \end{center} \caption{\small A sample} \label{tree} \end{figure} What should I do ? Could it be that their server is using an old compiler ? UPDATE : It finally worked. I converted the first image to PDF and the compilation happened perfectly. I guess it used the bounding box value from that PDF and applied it to all images.

    Read the article

  • Intrinsics program (SSE) - g++ - help needed

    - by Sriram
    Hi all, This is the first time I am posting a question on stackoverflow, so please try and overlook any errors I may have made in formatting my question/code. But please do point the same out to me so I may be more careful. I was trying to write some simple intrinsics routines for the addition of two 128-bit (containing 4 float variables) numbers. I found some code on the net and was trying to get it to run on my system. The code is as follows: //this is a sample Intrinsics program to add two vectors. #include <iostream> #include <iomanip> #include <xmmintrin.h> #include <stdio.h> using namespace std; struct vector4 { float x, y, z, w; }; //functions to operate on them. vector4 set_vector(float x, float y, float z, float w = 0) { vector4 temp; temp.x = x; temp.y = y; temp.z = z; temp.w = w; return temp; } void print_vector(const vector4& v) { cout << " This is the contents of vector: " << endl; cout << " > vector.x = " << v.x << endl; cout << " vector.y = " << v.y << endl; cout << " vector.z = " << v.z << endl; cout << " vector.w = " << v.w << endl; } vector4 sse_vector4_add(const vector4&a, const vector4& b) { vector4 result; asm volatile ( "movl $a, %eax" //move operands into registers. "\n\tmovl $b, %ebx" "\n\tmovups (%eax), xmm0" //move register contents into SSE registers. "\n\tmovups (%ebx), xmm1" "\n\taddps xmm0, xmm1" //add the elements. addps operates on single-precision vectors. "\n\t movups xmm0, result" //move result into vector4 type data. ); return result; } int main() { vector4 a, b, result; a = set_vector(1.1, 2.1, 3.2, 4.5); b = set_vector(2.2, 4.2, 5.6); result = sse_vector4_add(a, b); print_vector(a); print_vector(b); print_vector(result); return 0; } The g++ parameters I use are: g++ -Wall -pedantic -g -march=i386 -msse intrinsics_SSE_example.C -o h The errors I get are as follows: intrinsics_SSE_example.C: Assembler messages: intrinsics_SSE_example.C:45: Error: too many memory references for movups intrinsics_SSE_example.C:46: Error: too many memory references for movups intrinsics_SSE_example.C:47: Error: too many memory references for addps intrinsics_SSE_example.C:48: Error: too many memory references for movups I have spent a lot of time on trying to debug these errors, googled them and so on. I am a complete noob to Intrinsics and so may have overlooked some important things. Any help is appreciated, Thanks, Sriram.

    Read the article

  • SMS to server service

    - by duckofrubber
    Hi, I need to find a service that will allow me to send and receive SMS on a server for a project. The project requires that a user will have up to 8 keyword options to send, and will receive a different response back based on the keyword that they enter. Does anyone know of services that I could look into that will allow this? Thanks.

    Read the article

  • Is Form validation and Business validation too much?

    - by Robert Cabri
    I've got this question about form validation and business validation. I see a lot of frameworks that use some sort of form validation library. You submit some values and the library validates the values from the form. If not ok it will show some errors on you screen. If all goes to plan the values will be set into domain objects. Here the values will be or, better said, should validated (again). Most likely the same validation in the validation library. I know 2 PHP frameworks having this kind of construction Zend/Kohana. When I look at programming and some principles like Don't Repeat Yourself (DRY) and single responsibility principle (SRP) this isn't a good way. As you can see it validates twice. Why not create domain objects that do the actual validation. Example: Form with username and email form is submitted. Values of the username field and the email field will be populated in 2 different Domain objects: Username and Email class Username {} class Email {} These objects validate their data and if not valid throw an exception. Do you agree? What do you think about this aproach? Is there a better way to implement validations? I'm confused about a lot of frameworks/developers handling this stuff. Are they all wrong or am I missing a point? Edit: I know there should also be client side kind of validation. This is a different ballgame in my Opinion. If You have some comments on this and a way to deal with this kind of stuff, please provide.

    Read the article

  • How to define an n-m relation in doctrine?

    - by murze
    If got a table "Article" and a table "Tags". Articles can have multiple tags and tags can hang to multiple articles. The class BaseArticle looks like this: abstract class BaseArticle extends Doctrine_Record { public function setTableDefinition() { $this->setTableName('article'); $this->hasColumn('article_id', 'integer', 8, array( 'type' => 'integer', 'length' => 8, 'fixed' => false, 'unsigned' => false, 'primary' => true, 'autoincrement' => true, )); $this->hasColumn('title', 'string', null, array( 'type' => 'string', 'fixed' => false, 'unsigned' => false, 'primary' => false, 'notnull' => false, 'autoincrement' => false, )); $this->hasColumn('text', 'string', null, array( 'type' => 'string', 'fixed' => false, 'unsigned' => false, 'primary' => false, 'notnull' => false, 'autoincrement' => false, $this->hasColumn('url', 'string', 255, array( 'type' => 'string', 'length' => 255, 'fixed' => false, 'unsigned' => false, 'primary' => false, 'notnull' => false, 'autoincrement' => false, )); } public function setUp() { parent::setUp(); $this->hasMany('Tag as Tags', array( 'local' => 'article_id', 'foreign'=>'tag_id', 'refClass'=>'Articletag') ); } } The BaseTag-class like this: abstract class BaseTag extends Doctrine_Record { public function setTableDefinition() { $this->setTableName('tag'); $this->hasColumn('tag_id', 'integer', 4, array( 'type' => 'integer', 'length' => 4, 'fixed' => false, 'unsigned' => false, 'primary' => true, 'autoincrement' => true, )); $this->hasColumn('name', 'string', null, array( 'type' => 'string', 'fixed' => false, 'unsigned' => false, 'primary' => false, 'notnull' => false, 'autoincrement' => false, )); } public function setUp() { parent::setUp(); $this->hasMany('Article as Articles', array( 'local' => 'tag_id', 'foreign'=>'article_id', 'refClass'=>'Articletag') ); } } And the relationship class like this: abstract class BaseArticletag extends Doctrine_Record { public function setTableDefinition() { $this->setTableName('articletag'); $this->hasColumn('article_id', 'integer', 8, array( 'type' => 'integer', 'length' => 8, 'fixed' => false, 'unsigned' => false, 'primary' => true, 'autoincrement' => false, )); $this->hasColumn('tag_id', 'integer', 4, array( 'type' => 'integer', 'length' => 4, 'fixed' => false, 'unsigned' => false, 'primary' => true, 'autoincrement' => false, )); } public function setUp() { parent::setUp(); } } When I try to get a property from the article all goes well by using: $article = Doctrine_Query::create()->from('Article a') ->where('id = ?' , 1) ->fetchOne(); echo $article->title; //gives me the title But when I try this: foreach($article->Tags as $tag) { echo($tag->name) } I get an error: Unknown record property / related component "Tags" on "Article"

    Read the article

  • Dimension Mismatch MatLab; cant figure out why it is mismatching

    - by Abid
    I think it may be a syntax issue, here is the code. load ([ 'C:\Users\Abid\Desktop\Inquiry Runs\dtS' ]) dtS((dtS==0))=nan; for j=2:9; maxS=max(dtS(j,:)); minS=min(dtS(j,:)); maxval(j,:)=dtS((dtS>(maxS-.1*maxS))); minval(j,:)=dtS((dtS<(minS+.1*minS))); avmax(j)=mean(maxval(j,:)); avmin(j)=mean(minval(j,:)); avs(j,:)=[avmax(j) avmin(j)] end So I know the the row matrices are different sizes every loop. For example maxval(j,:) will change depending one row it is looking through for certain values. I did this manually and I see that on the first loop the matrices are size (1,1), however, if I set the loop to run for only j=2, the row length is 13. Usually if a matrix is changing size on the loop, I only get a warning, but this time I think it is due to a reason I don't understand.

    Read the article

  • MIME/IMF error codes?

    - by hack.augusto
    I need to write php code to identify common e-mail errors, like "inbox full" or specially "invalid email name" from email messages, because we need to clear our databases from nonexistent emails. I'm looking the MIME and IMF formats but I didn't find any kind of standard error code, does it exist?

    Read the article

  • java gui changing picture causes heapspace error

    - by pie154
    I have a java programme than when a button is clicked it updates the image on screen to the according image. this will work for the first 15 or so clicks then it causes a java heapspace error. I think it is because of the way I am updating the jpanel that contains the bufferedimage but not sure what the reason is. My code to get make the JPanel contain the new image is, public class extraScreenPanel { static JPanel screenPanel = new JPanel(new BorderLayout()); public static JPanel extraScreenPanel(int dispNum) { JLabel label = new JLabel("" + dispNum + ""); label.setPreferredSize(new Dimension(800, 600)); //label.setUI( new VerticalLabelUI(true) ); label.setVerticalAlignment( SwingConstants.TOP ); screenPanel = imgDisp(dispNum); label.setForeground(Color.white); label.setFont(new Font("Serif", Font.BOLD, 200)); screenPanel.add(label, BorderLayout.PAGE_END ); return screenPanel; } public static JPanel imgDisp(int picNum) { /* String url[] = new String[5000]; String part1; url[0] = "C:/PiPhotoPic/pic16.jpg"; for(Integer i=1;i<5000;i++){ if(i<10){part1 = "C:/temp/new0000000";} else if(i<100){part1 = "C:/temp/new000000";} else if(i<1000){part1 = "C:/temp/new00000";} else {part1 = "C:/temp/new00000";} String num = Integer.toString(i); url[i]= part1 + num + ".jpg"; } if(picNum<0){picNum=0;} String ref = url[picNum];*/ //this code is just to get specific ref for image location BufferedImage loadImg = loadImage(ref); JImagePanel panel = new JImagePanel(loadImg, 0, 0); panel.setPreferredSize(new Dimension(800, 600)); return panel; } public static class JImagePanel extends JPanel{ private BufferedImage image; int x, y; public JImagePanel(BufferedImage image, int x, int y) { super(); this.image = image; this.x = x; this.y = y; } @Override protected void paintComponent(Graphics g) { super.paintComponent(g); g.drawImage(image, x, y, null); } } public static BufferedImage loadImage(String ref) { BufferedImage bimg = null; try { bimg = javax.imageio.ImageIO.read(new File(ref)); } catch (Exception e) { e.printStackTrace(); } BufferedImage bimg2 = resize(bimg,800,600); return bimg2; } public static BufferedImage resize(BufferedImage img, int newW, int newH) { int w = img.getWidth(); int h = img.getHeight(); BufferedImage dimg = dimg = new BufferedImage(newW, newH, img.getType()); Graphics2D g = dimg.createGraphics(); g.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR); g.drawImage(img, 0, 0, newW, newH, 0, 0, w, h, null); g.dispose(); return dimg; } } And the code that updates my gui is, it works by removing the panel from its containg panel and then readding it to it. picPanel = imgDisp.imgDisp(num); repaintPicPanel(); public static void repaintPicPanel() { picPanel.removeAll(); menuPanel.remove(picPanel);; menuPanel.add(picPanel, BorderLayout.LINE_START); }

    Read the article

  • Best Work Queue service for distributed clusters

    - by onewheelgood
    Hi there. I require a simple work queue type system for asynchronous task management. I have looked at both beanstalkd and gearman. However, both these seem to assume that the client and the queue server are on the same network, and therefore that there will always be a reliable network between them. I need one that can support the client and server being in different places in the world, and be able to manage temporary loss of network connection between clusters. Ideally, this would work in such a way where I post a job to a local proxy that attempts to send it to the main queue server. If there is no network connection, it would try again later, however it would not lose the job or delay the client. Any recommendations?

    Read the article

  • PHP, is_array() generating an "Undefined property: stdClass::$crit " error

    - by Brook Julias
    is_array($src2->crit) is generating an "Undefined property: stdClass::$crit" error. The line throwing the error is: if(is_array($src2->crit) && count($src->crit) > 0){ $src2->crit is initialized here. $src2->crit = array(); $src2->crit[0] = new dataSet(); $src2->crit[0]->tblName = $tbl2; $src2->crit[0]->colName = "ID"; $src2->crit[0]->val = $elm->editID; When testing $src2->crit with this code. print("\$src->crit is a ".$src->crit."<br />"); print_r($src->crit); print("<br />"); This is returned. $src2->crit is a Array Array ( [0] => dataSet Object ( [tblName] => sExam [colName] => ID [val] => 10 ) ) What am I not seeing/understanding correctly? If print("\$src2->crit is a ".$src->crit."<br />") returns that it is an array then why is is_array($src2->$crit) generating an error?

    Read the article

  • C++ Operator overloading - 'recreating the Vector'

    - by Wallter
    I am currently in a collage second level programing course... We are working on operator overloading... to do this we are to rebuild the vector class... I was building the class and found that most of it is based on the [] operator. When I was trying to implement the + operator I run into a weird error that my professor has not seen before (apparently since the class switched IDE's from MinGW to VS express...) (I am using Visual Studio Express 2008 C++ edition...) Vector.h #include <string> #include <iostream> using namespace std; #ifndef _VECTOR_H #define _VECTOR_H const int DEFAULT_VECTOR_SIZE = 5; class Vector { private: int * data; int size; int comp; public: inline Vector (int Comp = 5,int Size = 0) : comp(Comp), size(Size) { if (comp > 0) { data = new int [comp]; } else { data = new int [DEFAULT_VECTOR_SIZE]; comp = DEFAULT_VECTOR_SIZE; } } int size_ () const { return size; } int comp_ () const { return comp; } bool push_back (int); bool push_front (int); void expand (); void expand (int); void clear (); const string at (int); int operator[ ](int); Vector& operator+ (Vector&); Vector& operator- (const Vector&); bool operator== (const Vector&); bool operator!= (const Vector&); ~Vector() { delete [] data; } }; ostream& operator<< (ostream&, const Vector&); #endif Vector.cpp #include <iostream> #include <string> #include "Vector.h" using namespace std; const string Vector::at(int i) { this[i]; } void Vector::expand() { expand(size); } void Vector::expand(int n ) { int * newdata = new int [comp * 2]; if (*data != NULL) { for (int i = 0; i <= (comp); i++) { newdata[i] = data[i]; } newdata -= comp; comp += n; delete [] data; *data = *newdata; } else if ( *data == NULL || comp == 0) { data = new int [DEFAULT_VECTOR_SIZE]; comp = DEFAULT_VECTOR_SIZE; size = 0; } } bool Vector::push_back(int n) { if (comp = 0) { expand(); } for (int k = 0; k != 2; k++) { if ( size != comp ){ data[size] = n; size++; return true; } else { expand(); } } return false; } void Vector::clear() { delete [] data; comp = 0; size = 0; } int Vector::operator[] (int place) { return (data[place]); } Vector& Vector::operator+ (Vector& n) { int temp_int = 0; if (size > n.size_() || size == n.size_()) { temp_int = size; } else if (size < n.size_()) { temp_int = n.size_(); } Vector newone(temp_int); int temp_2_int = 0; for ( int j = 0; j <= temp_int && j <= n.size_() && j <= size; j++) { temp_2_int = n[j] + data[j]; newone[j] = temp_2_int; } //////////////////////////////////////////////////////////// return newone; //////////////////////////////////////////////////////////// } ostream& operator<< (ostream& out, const Vector& n) { for (int i = 0; i <= n.size_(); i++) { //////////////////////////////////////////////////////////// out << n[i] << " "; //////////////////////////////////////////////////////////// } return out; } Errors: out << n[i] << " "; error C2678: binary '[' : no operator found which takes a left-hand operand of type 'const Vector' (or there is no acceptable conversion) return newone; error C2106: '=' : left operand must be l-value As stated above, I am a student going into Computer Science as my selected major I would appreciate tips, pointers, and better ways to do stuff :D

    Read the article

  • Haskell Type error

    - by Jon
    I am getting a Couldn't match expected type error on this code and am not sure why. Would appreciate it if someone could point me in the right direction as to fixing it. import qualified Data.ByteString.Lazy as S import Data.Binary.Get import Data.Word getBinary :: Get Word16 getBinary = do a <- getWord16be "Test.class" return (a) main :: IO () main = do contents <- S.getContents print getBinary contents Specifically it cannot match expected type 'S.ByteString - IO ()' to inferred type 'IO ()'

    Read the article

  • Truly declarative language?

    - by gjvdkamp
    Hi all, Does anyone know of a truly declarative language? The behaviour I'm looking for is kind of what Excel does, where I can define variables and formulas, and have the formula's result change when the input changes (without having set the answer again myself) The behaviour I'm looking for is best shown with this pseudo code: X = 10 // define and assign two variables Y = 20; Z = X + Y // declare a formula that uses these two variables X = 50 // change one of the input variables ?Z // asking for Z should now give 70 (50 + 20) I've tried this in a lot of languages like F#, python, matlab etc, but every time i try this they come up with 30 instead of 70. Wich is correct from an imperative point of view, but i'm looking for a more declerative behaviour if you know what i mean. And this is just a very simple calculation. When things get more difficult it should handle stuff like recursion and memoization automagically. The code below would obviously work in C# but it's just so much code for the job, i'm looking for something a bit more to the point without all that 'technical noise' class BlaBla{ public int X {get;set;} // this used to be even worse before 3.0 public int Y {get;set;} public int Z {get{return X + Y;}} } static void main(){ BlaBla bla = new BlaBla(); bla.X = 10; bla.Y = 20; // can't define anything here bla.X = 50; // bit pointless here but I'll do it anyway. Console.Writeline(bla.Z);// 70, hurray! } This just seems like so much code, curly braces and semicolons that add nothing. Is there a language/ application (apart from Exel) that does this? Maybe I'm no doing it right in the mentioned langauges, or I've completely missed an app that does just this. I prototyped a language/ application that does this (along with some other stuff) and am thinking of productizing it. I just can't believe it's not there yet. Don't want to waste my time. Thanks in advance, Gert-Jan

    Read the article

  • sending SMS with VBA

    - by I__
    does anyone know if this is possible? i was able to succesfully run hyperterminal and use it to send texts through my phone which is attached by USB. anyone know how to do it in VBA?

    Read the article

  • Sorting out POCO, Repository Pattern, Unit of Work, and ORM

    - by CoffeeAddict
    I'm reading a crapload on all these subjects: POCO Repository Pattern Unit of work Using an ORM mapper ok I see the basic definitions of each in books, etc. but I can't visualize this all together. Meaning an example structure (DL, BL, PL). So what, you have your DL objects that contain your CRUD methods, then your BL objects which are "mapped" using an ORM back to your DL objects? What about DTOs...they're your DL objects right? I'm confused. Can anyone really explain all this together or send me example code? I'm just trying to put this together. I am determining whether to go LINQ to SQL or EF 4 (not sure about NHibrernate yet). Just not getting the concepts as in physical layers and code layers here and what each type of object contains (just properties for DTOs, and CRUDs for your core DL classes that match the table fields???). I just need some guidance here. I'm reading Fowler's books and starting to read Evans but just not all there yet.

    Read the article

  • What is the suggested way to show exception messages on UI which were produced in Business Layer?

    - by burak ozdogan
    Hi, Is there a pattern OR 'a best practice' on creating user's friendly messages in the presentation layer by using exceptions which were thrown from the Business Layer? Actually in many cases I prefer to throw Application Exceptions and this is forcing me to catch them on UI (aspx.cs pages). And if the process is complex which may produce many different types of exceptions I have to have many catch blocks to produce specific error messages. Is there a better way coming to your mind? A pattern maybe for similar cases? thanks

    Read the article

  • General ORM design question

    - by Calvin
    Suppose you have 2 classes, Person and Rabbit. A person can do a number of things to a rabbit, s/he can either feed it, buy it and become its owner, or give it away. A rabbit can have none or at most 1 owner at a time. And if it is not fed for a while, it may die. Class Person { Void Feed(Rabbit r); Void Buy(Rabbit r); Void Giveaway(Person p, Rabbit r); Rabbit[] rabbits; } Class Rabbit { Bool IsAlive(); Person pwner; } There are a couple of observations from the domain model: Person and Rabbit can have references to each other Any actions on 1 object can also change the state of the other object Even if no explicit actions are invoked, there can still be a change of state in the objects (e.g. Rabbit can be starved to death, and that causes it to be removed from the Person.rabbits array) As DDD is concerned, I think the correct approach is to synchronize all calls that may change the states in the domain model. For instance, if a Person buys a Rabbit, s/he would need to acquire a lock in Person to make a change to the rabbits array AND also another lock in Rabbit to change its owner before releasing the first one. This would prevent a race condition where 2 Persons claim to be the owner of the little Rabbit. The other approach is to let the database to handle all these synchronizations. Who makes the first call wins, but then the DB needs to have some kind of business logics to figure out if it is a valid transaction (e.g. if a Rabbit already has an owner, it cannot change its owner unless the Person gives it away). There are both pros/cons in either approach, and I’d expect the “best” solution would be somewhere in-between. How would you do it in real life? What’s your take and experience? Also, is it a valid concern that there can be another race condition the domain model has committed its change but before it is fully committed in the database? And for the 3rd observation (i.e. state change due to time factor). How will you do it?

    Read the article

  • Build custom error messages in model files (example: using the 'pluralize' method)

    - by user502052
    I am using Ruby on Rails 3.0.7 and I would like to use the pluralize method in a my model file in order to properly build custom error messages. For example, I would like to do something like the following: NAME_MIN_LENGHT = 2 # Is 2 but I plan to change that (maybe dynamically... if it is possible) in future development validates :name, :length => { :minimum => NAME_MIN_LENGHT, :too_short => "is too short (minimum is #{pluralize(NAME_MIN_LENGHT, "character")})", }, How can I do that? Is it advisable? Why?

    Read the article

< Previous Page | 74 75 76 77 78 79 80 81 82 83 84 85  | Next Page >